BACKGROUND:Paronychia has been reported in as many as 10% of patients treated with gefitinib. Although conservative management and treatment with topical or systemic antibiotics are beneficial, no effective method exists for intractable cases. Platelet-rich plasma (PRP)consists of a high concentration of platelets that promote wound healing through chemotaxis, cell proliferation,angiogenesis, and tissue remodeling. OBSERVATIONS:We herein report a refractory case of gefitinib-induced paronychia successfully treated with autologous PRP. A 68-year-old woman who had been diagnosed as having lung adenocarcinoma with multiple bone and brain metastases initiated gefitinib therapy at an oral dose of 250 mg/d. After 1 month, multiple paronychia with periungual granulation appeared on the nailfold of the first, second, and third toenails of both feet.Because the paronychia recurred repeatedly despite use of a topical antibiotic, topical corticosteroid, and short term systemic antibiotic, she started PRP treatment. After 3 months, the lesion showed marked improvement with minimal pain or discharge. CONCLUSION:This case highlights the therapeutic challenges of using PRP to promote tissue repair in intractable gefitinib-induced paronychia and merits further investigation.